No offense taken. It IS a Huffy after all. The rear axle set-up weighs more than the rest of the bike. One reason I question the need for a differential. I have read of single-drive wheel trikes having a tendency to pull to one side, and it sounded like the differential was a means to correct that.
We have considered a completely custom built trike as well, but that defeats the purpose of getting this back on the streets where it belongs.